E-ACSL: proper bitfileds handling

ID0002305: This issue was created automatically from Mantis Issue 2305. Further discussion may take place here.

Id	Project	Category	View	Due Date	Updated
ID0002305	Frama-C	Plug-in > E-ACSL	public	2017-05-29	2018-11-30


Reporter	evdenis	Assigned To	fmaurica	Resolution	fixed
Priority	normal	Severity	minor	Reproducibility	always
Platform	-	OS	-	OS Version	-
Product Version	Frama-C 14-Silicon	Target Version	Frama-C 18-Argon	Fixed in Version	Frama-C 18-Argon

Description :

E-ACSL generates code which takes address from bitfields. This leads to compilation error.

Test: #include <stdbool.h>

struct bitfields { int i : 2; bool j : 1; } t;

int test(struct bitfields *a) { return a->i; }

int main(int argc, char **argv) { //@ assert \valid_read(&(t.j)); t.j = 1; return test(&t); }

E-ACSL code: struct bitfields t; int test(struct bitfields a) { int __retres; /@ assert rte: mem_access: \valid_read(&a->i); */ { int __gen_e_acsl_valid_read; __e_acsl_store_block((void *)(& a),4U); __gen_e_acsl_valid_read = __e_acsl_valid_read((void *)(& a->i), // ERROR sizeof(int)); __e_acsl_assert(__gen_e_acsl_valid_read,(char *)"Assertion", (char *)"test", (char *)"rte: mem_access: \valid_read(&a->i)",10); __retres = (int)a->i; } __e_acsl_delete_block((void *)(& a)); return __retres; }

int main(int argc, char **argv) { int tmp; __e_acsl_memory_init(& argc,& argv,4U); __e_acsl_globals_init(); /*@ assert \valid_read(&t.j); */ { int __gen_e_acsl_valid_read; __gen_e_acsl_valid_read = __e_acsl_valid_read((void *)(& t.j), // ERROR sizeof(_Bool)); __e_acsl_assert(__gen_e_acsl_valid_read,(char *)"Assertion", (char *)"main",(char *)"\valid_read(&t.j)",15); } __e_acsl_initialize((void *)(& t.j),sizeof(_Bool)); //ERROR t.j = (_Bool)1; tmp = test(& t); __e_acsl_delete_block((void *)(& t)); __e_acsl_memory_clean(); return tmp; }

GCC Output on E-ACSL code:

gcc ./generated.c

generated.c: In function ‘test’: generated.c:86:60: error: cannot take address of bit-field ‘i’ __gen_e_acsl_valid_read = __e_acsl_valid_read((void *)(& a->i), ^ generated.c: In function ‘main’: generated.c:112:60: error: cannot take address of bit-field ‘j’ __gen_e_acsl_valid_read = __e_acsl_valid_read((void *)(& t.j), ^ generated.c:117:32: error: cannot take address of bit-field ‘j’ __e_acsl_initialize((void *)(& t.j),sizeof(_Bool));

Additional Information :

Quickfix (doesn't handle __e_acsl_initialize): diff --git a/translate.ml b/translate.ml index b5229db..1ea272e 100644 --- a/translate.ml +++ b/translate.ml @@ -704,7 +704,17 @@ and named_predicate_content_to_exp ?name kf env p = | Pvalid_read _ -> "valid_read" | _ -> assert false in

 mmodel_call_with_size ~loc kf name Cil.intType env t

 let ptyp = Cil.unrollType(Typing.typ_of_term(t)) in

```
 let typ = match ptyp with
```
```
           | TPtr(a,_) -> a
```
```
           | _ -> assert false
```
```
 in
```
```
 let attr = Cil.typeAttrs typ in
```

 if Cil.hasAttribute Cil.bitfield_attribute_name attr

```
 then
```

    not_yet env "Can't take address from variable with bitfield."

```
 else
```
```
    mmodel_call_with_size ~loc kf name Cil.intType env t
```
in if !is_visiting_valid then begin (* we already transformed \valid(t) into \initialized(&t) && \valid(t):

Steps To Reproduce :

frama-c -e-acsl-prepare -rte -rte-precond ./bf.c -then -e-acsl -then-last -print

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